Superdome Servers - I/O Expansion Cabinet Guide, Fifth Edition

Appendix B
Site Requirements
Environmental Requirements
216
The following three types of air distribution system are listed in order of recommendation:
• Underfloor air distribution system—Downflow air conditioning equipment located on the raised floor of
the computer room uses the cavity beneath the raised floor as plenum for the supply air.
Return air from an underfloor air distribution system can be room space return air (RSRA), as shown in
Figure B-2 on page 217, or ducted return air (DRA) above the ceiling, as shown in Figure B-3 on page 218.
Perforated floor panels (available from the raised floor manufacturer) should be located around the
perimeter of the system cabinets. Supply air emitted though the perforated floor panels is then available
near the cooling air intake vents of the computer system cabinets.
• Ceiling plenum air distribution system—Supply air is ducted into the ceiling plenum from upflow air
conditioning equipment located in the computer room or from an air handling unit (remote).
The ceiling construction should resist air leakage. Place perforated ceiling panels (with down discharge
air flow characteristics) around the perimeter of the system cabinets. The supply air emitted downward
from the perforated ceiling panels is then available near the cooling air intake vents of the computer
system cabinets.
Return air should be ducted back to the air conditioning equipment though the return air duct above the
ceiling.
• Above ceiling ducted air distribution system—Supply air is ducted into a ceiling diffuser system from
upflow air conditioning equipment located in the computer room or from an air handling unit (remote).
Return air from an above ceiling ducted air distribution system may be ducted return air (DRA) above the
ceiling, as shown in Figure B-2 on page 217, or ceiling plenum return air (CPRA), as shown in Figure B-3
on page 218.
Adjust the supply air diffuser system grilles to direct the cooling air downward around the perimeter of
the computer system cabinets. The supply air is then available near the cooling air intake vents of the
computer system cabinets.
Air Conditioning System Installation
All air conditioning equipment, materials, and installation must comply with any applicable construction
codes. Installation of the various components of the air conditioning system must also conform to the air
conditioning equipment manufacturer’s recommendations.
Figure B-2 on page 217 illustrates a typical computer room underfloor air distribution system (RSRA).
Figure B-3 on page 218 illustrates a typical computer room underfloor air distribution system (DRA).
Figure B-4 on page 219 illustrates a typical computer room ceiling plenum air distribution system (CPRA).